This invention is related to the distribution of broadband services within a subscriber""s service location and more specifically to distributing telephone and broadband services within a subscriber""s service location using the existing copper pairs already located within the service location.
Due to the tremendous costs associated with ubiquitous deployment of fiber in a subscriber loop it is extremely desirable to use the existing subscriber loop plant to carry both plain old telephone service (POTS) and broadband services such as internet data, digital video, and multimedia services. Asymmetric Digital Subscriber Line (ADSL) technology has demonstrated the viability of a subscriber loop twisted pair cable to carry both ADSL and POTS or narrowband signals. By ADSL technology a broadband signal, called an ADSL signal, and POTS signals are multiplexed by a device called an ADSL POTS splitter and transmitted from a service provider""s central office over the subscriber loop to the subscriber location, e.g. a residential unit or home. An ADSL POTS splitter at the subscriber""s residence demultiplexes and transmits the POTS signal onto one wire pair and transmits the ADSL signal onto a separate wire pair. The POTS signal is terminated on a telephone and the ADSL signal is terminated on an ADSL remote terminal unit, known in the art as an ATU-R. Current ADSL systems can deliver up to 8,000,000 b/s (8 Mb/s) to a subscriber""s residence.
Once a high bit rate digital signal reaches the subscriber""s residence, as in an ADSL signal over the outside plant twisted pairs, it still needs to be distributed within that location. Although ADSL has been demonstrated to be viable technology for the twisted pairs residing outside the home, ADSL is neither technically nor economically attractive for distribution within the home. For one, the price of ATU-Rs will preclude a subscriber from having more than one ATU-R per subscriber residence or location. Secondly, within the subscriber service location ADSL is also particularly susceptible to high frequency noise that is generated within the home and from sources outside the home, e.g., AM radio stations, because the cable within the home is often untwisted. As a result broadband digital networks such as 10Base-T, 100Base-T, ATM, and IEEE 1394 will increasingly be installed in service locations to distribute the aforementioned broadband services. These broadband digital networks will have to be more cost effective to deploy within a residence and should not suffer from the technical limitations of ADSL.
Because an overwhelming majority of service locations are already wired with existing telephone house wiring or cable it would prove extremely cost effective to be able to distribute the aforementioned broadband digital signals over this existing telephone cable within the residential unit. Residential telephone cable is often in a sheath with four untwisted conductors or wires. These wires have various names including quad, station wire, phone wire and telephone station wire. Quad contains black, green, red, and yellow insulated copper conductors. Typically the green and red conductors are paired together and used for a first plain old telephone service (POTS) line. The yellow and black conductors are also typically paired together for a second POTS line.
Conventional wisdom has precluded use of residential cable for carrying broadband services if that cable is already being used to carry POTS. For example, 10Base-T requires two pairs of wire for transmission, one pair for transmit and one pair for receive. As a result, the prior art suggests that if a quad cable carries 10Base-T then the cable has no additional capacity for carrying POTS and vice versa. As such, it is thought that additional and separate cabling, e.g., coaxial cable, will be required at the service location to carry the broadband services.
It is therefore an object of the present invention to provide a method and apparatus that allows POTS signals and broadband signals to be simultaneously carried on existing quad cable at the service location.
My invention involves an apparatus, namely a broadband transceiver, that allows one or two POTS lines and a broadband signal all to be carried simultaneously on two untwisted pairs of copper wire within a service location. My invention combines a POTS signal and a broadband signal on a single pair of wires by frequency division multiplexing. Both signals are therefore isolated from each other and can be transmitted to their ultimate destination in the service location. The same apparatus also demultiplexes the POTS signal and the broadband signal carried on a single pair of wires by frequency division multiplexing.
Accordingly it is an aspect of my invention to distribute POTS and broadband signals within a subscriber home over a single quad cable. By frequency division multiplexing and demultiplexing the narrowband or telephone and the broadband signals on broadband transceivers at convenient points within the subscriber location each telephone or broadband termination device, e.g., a computer or high definition television, is able to receive, respectively, a telephone or broadband signal.
In accordance with my invention, a broadband transceiver can be used in conjunction with ADSL technology to distribute the broadband signal carried by an ADSL at the subscriber location providing a much more cost effective method for distribution of broadband signals, and in particular ADSL signals, within the home. For example, by my invention a subscriber is required to purchase only one ADSL POTS splitter and one ATU-R in order to support a plurality of broadband termination devices and telephones installed within the subscriber residence.
Significantly both POTS and broadband digital traffic can advantageously be simultaneously carried on existing residential telephone cables or quads. As a result a subscriber may be provided with up to three services over existing residential telephone cable. For example, a subscriber may have access to two POTS lines and one ADSL data line.
Accordingly, my invention includes a method for distributing narrowband and broadband signals arriving at a subscriber service location using the existing copper wires located within the subscriber service location and including the steps of receiving and separating the narrowband and broadband signals within the location; in response to the broadband signals generating a broadband digital signal operating at frequencies greater than 1,000,0000 Hz (1 MHz); combining said narrowband and said broadband digital signals at a first broadband transceiver; uncombining said combined narrowband and broadband digital signals at a second broadband transceiver; and applying the narrowband and broadband digital signals egressing the second broadband transceiver separately to the appropriate service termination devices. While my invention is most advantageously utilized to distribute within a residence the narrowband and broadband signals transmitted, as by ADSL signals, from the outside plant, it may also be employed for distribution of broadband signals originating within the residence.